Photon localization is the fundamental property of microstructure fibers. A method of coherent back scattering for measurement on micro-structure optical fibers (MOFs) is proposed. In order to understand and explain the theory of photon localization, the quartz-crystal, integrated multimillion micro-structure optical fiber and dual-core micro-structure optical fiber were measured in the visible region. Based on the wave classical transmission theory, the experimental equipment for the measurement was setup. The experimental results reveal that there is not interference phenomenon for quartz-crystal, but some strong interference apexes for micro-structure optical fibers at 575 nm. Because of the existence of the periodic structure from the vein region to the node region in 2D micro-structure optical fibers, the dimension is around 500～600 nm which is corresponding to some discontinuous scattered particles, when the wavelength is 575 nm, the dimension is close to the particles which meets the condition of photon localization. Therefore, the phenomena of strong coherent back scattering come into being.